1. Erneuerbare Energien weltweit: Globaler Stand 2018;Hilgedieck;BWK,2019
2. EC Clean Energy for All Europeans
https://ec.europa.eu/energy/topics/energy-strategy/clean-energy-all-europeans_en
3. IRENA Renewable Energy Capacity Statistics 2020 International Renewable Energy Agency
https://irena.org/-/media/Files/IRENA/Agency/Publication/2020/Mar/IRENA_RE_Capacity_Statistics_2020.pdf
4. https://webstore.iea.org/key-world-energy-statistics-2019